Methods and apparatuses for edge finishing glass substrates

ABSTRACT

A glass support system for a glass edge finishing apparatus includes a vacuum member that is configured to extend lengthwise in a glass feed direction and along an edge of a glass substrate. The vacuum member has a vacuum body that includes a pressure chamber located therein and a support surface having an array of vacuum openings extending therethrough and in communication with the pressure chamber. The array of vacuum openings is arranged in multiple, side-by-side rows with substantially uniform spacing between the vacuum openings along each one of the multiple rows.

This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/194,952, filed on Jul. 21, 2015, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND Field

The present disclosure relates to methods and apparatuses for edge finishing glass substrates and, more particularly, to methods and apparatuses used to increase symmetry of edge beveling.

Technical Background

Conventional glass edge finishing apparatuses have been developed largely for relatively thick glass substrates having relatively high stiffness compared to thinner glass substrates. As one example, glass sheets, after having been formed using a mechanical scoring and breaking process, typically have edges that are ground using an abrasive grinding wheel. In certain applications, for example in the automotive industry, it may be desirable to provide the edges of the glass sheets with a rounded profile on the outer periphery of the glass sheets.

Flat panel displays and other applications often use much thinner glass sheets than are employed in the automotive industry. Thinner glass sheets can have a reduced stiffness and increased flexibility compared to the thicker glass sheets. Edge finishing such thin glass sheets having reduced stiffness and increased flexibility can introduce challenges due, at least in part, to the forces involved in the edge finishing process. Accordingly, there is need for methods and apparatuses for edge finishing glass substrates including relatively thin glass substrates.

SUMMARY

One technique to improve the mechanical reliability of flexible glass substrates is to grind and polish edges of the flexible glass substrates to remove undesirable cracks and fractures in the flexible glass layer, for example, in order to achieve a predetermined edge strength. To this end, methods and apparatuses for finishing glass substrates are described herein where edge finishing apparatuses are used to effectively finish the glass substrates, while providing the edge with a rounded shape in a process referred to herein as beveling.

According to one embodiment, a glass support system for a glass edge finishing apparatus includes a vacuum member, for example, a vacuum chuck that is configured to extend lengthwise in a glass feed direction and along an edge of a glass substrate. The vacuum member comprises a vacuum body that includes a pressure chamber located therein and a support surface comprising an array of vacuum openings extending therethrough and in communication with the pressure chamber. The array of vacuum openings is arranged in multiple, side-by-side rows comprising substantially uniform spacing between the vacuum openings along each one of the multiple rows.

According to another embodiment, a glass edge finishing apparatus includes a glass transport system and a glass support system that is moved by the glass transport system in a glass feed direction. The glass support system can be configured to support a glass substrate having a thickness of no more than about 0.7 mm. The glass substrate comprises a generally planar surface and an out-of-plane direction normal to the generally planar surface. The glass feed direction is normal to the out-of-plane direction. The glass support system can include a vacuum member, for example, a vacuum chuck configured to extend lengthwise in the glass feed direction and along an edge of the glass substrate. The vacuum member comprises a vacuum body including a pressure chamber located therein and may further include a support surface comprising an array of vacuum openings extending therethrough and in communication with the pressure chamber. The array of vacuum openings can include at least about 25 openings per 100 cm² of support surface area.

According to yet another embodiment, a method of finishing an edge of a glass substrate with a thickness equal to or less than about 0.7 mm is provided. The method includes supporting the glass substrate on a glass support system. The glass substrate comprises a generally planar surface, an out-of-plane direction normal to the generally planar surface and a glass feed direction being normal to the out-of-plane direction. The glass support system may include a vacuum member, for example, a vacuum chuck, configured to extend lengthwise in the glass feed direction and along an edge of the glass substrate. The vacuum member can comprise a vacuum body including a pressure chamber located therein and a support surface comprises an array of vacuum openings extending therethrough and in communication with the pressure chamber. The array of vacuum openings may include at least about 25 openings per 100 cm² of support surface area. A negative pressure can be applied through the array of vacuum openings to the generally planar surface facing the vacuum member. The edge of the glass substrate may be beveled using an abrasive wheel assembly.

According to yet another embodiment, a glass edge finishing apparatus includes a glass transport system and a glass support system that is moved by the glass transport system in a glass feed direction. The glass support system may be configured to support a glass substrate with a thickness of no more than about 0.7 mm. The glass substrate comprises a generally planar surface and an out-of-plane direction normal to the generally planar surface. The glass feed direction is normal to the out-of-plane direction. The glass support system can include a vacuum member, for example, a vacuum chuck, configured to extend lengthwise in the glass feed direction and along an edge of the glass substrate. The vacuum member may include a vacuum body including a pressure chamber located therein and a support surface having a plurality of vacuum openings extending therethrough and in communication with the pressure chamber. An abrasive wheel assembly may also be provided, the abrasive wheel assembly configured to bevel the edge of the glass substrate as the glass substrate is moved by the abrasive wheel assembly in the glass feed direction by the glass transport system. An edge guide assembly may be located between the abrasive wheel assembly and the vacuum member and can include an upper edge guide member and a lower edge guide member spaced from the upper edge guide member to provide a path through which the glass substrate can travel.

Additional features and advantages described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present disclosure are better understood when the following detailed description of the disclosure is read with reference to the accompanying drawings, in which:

FIG. 1 illustrates a beveled edge of a glass substrate;

FIG. 2 illustrates a plot showing a relationship between out-of-plane vertical displacement of glass edge and resulting edge bevel asymmetry;

FIG. 3 is a schematic illustration of a glass finishing apparatus;

FIG. 4 is a detail view of a vacuum member and glass substrate for use in the finishing apparatus of FIG. 3;

FIG. 5 illustrates a plot showing glass edge flatness;

FIG. 6 is a top view of the vacuum member of FIG. 4 shown in isolation;

FIG. 7 illustrates a perspective view of an exemplary vacuum member;

FIG. 8 illustrates a section view of the vacuum member of FIG. 7;

FIG. 9 illustrates a section view of another exemplary vacuum member;

FIG. 10 illustrates a section view of another exemplary vacuum member;

FIG. 11 illustrates a top view of another exemplary vacuum member;

FIG. 12 illustrates a top view of yet another exemplary vacuum member;

FIG. 13 illustrates a top view of another exemplary vacuum member;

FIG. 14 is a schematic illustration of a glass support structure including multiple vacuum members;

FIG. 15 illustrates a schematic, detail view of an abrasive wheel for use in the glass finishing apparatus of FIG. 3;

FIG. 16 is a plot illustrating decreased edge bevel asymmetry provided through the use of a regular distribution of vacuum openings;

FIG. 17 is a plot of glass stiffness versus position along a glass substrate;

FIG. 18 is a plot illustrating flexural rigidity of a glass substrate versus thickness of the glass substrate;

FIG. 19 is a schematic illustration of an edge guide assembly and abrasive wheel;

FIG. 20 is a schematic illustration of an edge guide assembly;

FIG. 21 illustrates a glass edge finishing apparatus;

FIG. 22 illustrates another view of the glass edge finishing apparatus of FIG. 21;

FIG. 23 illustrates another glass edge finishing apparatus;

FIG. 24 Illustrates another view of the glass edge finishing apparatus of FIG. 23;

FIG. 25 is a schematic illustration of an edge guide assembly;

FIG. 26 is another illustration of an edge guide assembly;

FIG. 27 is another illustration of an edge guide assembly; and

FIG. 28 illustrates a representative plot illustrating decreased edge bevel asymmetry provided through use of an edge guide assembly.

DETAILED DESCRIPTION

Although glass is an inherently strong material, its strength and mechanical reliability are a function of its surface defect or flaw size density distribution and the cumulative exposure of the material to stress over time. Edge strength can be an important factor for mechanical reliability of glass substrates. During an entire product life cycle, glass substrates may be subjected to various kinds of static and dynamic mechanical stresses. Embodiments described herein generally relate to methods and apparatuses for finishing glass substrates where edge finishing apparatuses are used to effectively finish the glass substrates and to improve edge strength and mechanical reliability of glass substrates.

Glass substrates that are trimmed from glass ribbon, or from larger glass substrates, tend to have sharp edges formed during trimming operations. The sharp edges of the glass substrates are prone to damage during handling. Edge flaws, for example chips, cracks, and the like, may decrease the strength of the glass. The edges of the glass substrates may be processed to remove the sharp edges by grinding and shaping, for example beveling, to eliminate sharp edges that are easily damaged. By removing the sharp edges from the glass substrates, flaws in the glass substrate may be minimized, thereby reducing the likelihood of damage to the glass plate during handling.

A variety of abrasive wheels may be used to grind and shape the edges of glass substrates, including use of “cup” wheels and “formed” wheels. Cup wheels are generally circular in shape and include a recessed center region spaced apart from the circumference of the cup wheel. The cup wheel is brought into contact with the glass substrates where the planar faces of the cup wheel contact the glass substrates while the circumferential faces of the cup wheel are spaced apart from the glass substrates. Formed wheels include a groove positioned in an edge of the circumferential faces of the formed wheel. The groove includes a profile that corresponds to the processed shape of the substrate edge. The groove of the formed wheel is brought into contact with the edges of the glass substrates to grind and shape the edges.

Referring to FIG. 1, illustrating an exemplary substrate edge 12, the term “first surface,” and other variations thereof, is used herein to denote a first, relatively flat region of a glass substrate 10. The first surface is denoted by 14 in FIG. 1. Similarly, the term “second surface,” and other variations thereof, is used herein to denote a second, relatively flat surface region of the substrate 10, which is substantially parallel to the first surface 14. The second surface is denoted by 16 in FIG. 1.

The terms “first bevel,” “first bevel section,” and other variations thereof, are used herein to denote a first portion of the substrate edge, located between the first surface 14 and an apex 18 of the substrate edge 12. The first bevel is denoted by 20 in FIG. 1. Similarly, the terms “second bevel” and “second bevel section” and other variations thereof are used herein to denote a second portion of the substrate edge, located between the second surface 16 and the apex 18. The second bevel is denoted by 22 in FIG. 1. In certain embodiments, the first and second bevels 20 and 22 may be curved, as shown in FIG. 1; however, the first and second bevels may, in other non-limiting embodiments, be relatively planar.

The term “apex,” and other variations thereof, is used herein to denote the end region of the substrate edge 12, where the first and second bevels 20 and 22 converge. It is noted that FIG. 1 depicts the apex 18 as a flat area having a given length; however the apex 18 can also be a finite point where the first and second bevels meet, such that the substrate 12 edge is a substantially continuous curve from surface 14 to surface 16.

The term “first bevel-surface interface,” and other variations thereof, is used herein to denote the region where the first bevel section meets the relatively flat first surface 14. The first bevel-surface interface is denoted by 26 in FIG. 1. Similarly, the term “second bevel-surface interface,” and other variations thereof, is used herein to denote the region where the second bevel section meets the relatively flat second surface 16. The second bevel-surface interface is denoted by 28 in FIG. 1.

The glass substrate 10 may be a flexible glass substrate having a thickness 30 of about 0.3 mm or less including but not limited to thicknesses of, for example, in a range from about 0.01 to about 0.200 mm, for example, in a range from about 0.05 mm to about 0.1 mm, from about 0.1 to about 0.15 mm, from about 0.15 to about 0.3 mm, from about 0.100 to about 0.200 mm, including all ranges and subranges therebetween. Exemplary thicknesses can include 0.3, 0.275, 0.25, 0.225, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01 mm. In some embodiments, the glass substrate 10 may have a thickness 30 equal to or less than about 0.7 mm. The glass substrate 10 may be formed of glass, a glass ceramic or composites thereof. A fusion process (e.g., downdraw process) that forms high quality glass substrates can be used in a variety of devices and one such application is flat panel displays. Glass substrates produced in a fusion process have surfaces with superior flatness and smoothness when compared to glass substrates produced by other methods. The fusion process is described in U.S. Pat. Nos. 3,338,696 and 3,682,609. Other suitable glass substrate forming methods include a float process, updraw and slot draw methods.

Without wishing to be bound by theory, for relatively thin glass substrates 10 (equal to or less than about 0.7 mm), symmetrical shape characteristics with respect to first bevel-surface interface 26 and the second bevel-surface interface 28 for a horizontally oriented glass substrate 10 can have a direct effect on edge resistance to plastic deformation during bending of the glass substrate 10. The edge asymmetry between the first bevel section 20 and the second bevel section 22, sometimes referred to herein as “edge bevel asymmetry,” is directly related to edge strength for the glass substrates 10. Edge bevel asymmetry may be measured by the respective widths W₁ and W₂ of the first and second bevel sections 20 and 22 to the apex 18 in the direction of substrate thickness 30. Deflection of the substrate edge 12 out of the plane of the glass substrate 10 (vertical displacement) during the beveling process can produce edge bevel asymmetry. FIG. 2 illustrates an exemplary relationship between deflection of the substrate edge 12 and resulting edge bevel asymmetry for a glass substrate 10 having a thickness of about 0.5 mm. As can be seen, at position range R, deflection of the substrate edge 12 increases substantially (as shown by line 31) resulting in an increase in edge bevel asymmetry (as shown by lines 32 and 40).

Edge horizontal flatness (i.e., minimal vertical displacement), particularly for thin glass substrates 10, can be influenced by the effectiveness of support during a beveling process. Referring to FIG. 3, a glass edge finishing apparatus 40 suitable for performing a beveling process includes a support device 42 comprising a glass transport system 44 and a glass support system 46. The glass transport system 44 can move (e.g., translate) the glass support system 46 in a feed direction, which can be generally aligned (parallel) with an edge 48 of a glass substrate 50. The glass support system 46 may be carried with or otherwise moved by the glass transport system 44 in the feed direction. The glass support system 46 includes a vacuum system 52 that includes edge vacuum members 54 and 56, for example, vacuum chucks, that extend along opposite edges 48 and 58 of the glass substrate 50 and, in some embodiments, along substantially the entire length of the glass substrate 50 in the feed direction. In some embodiments, the vacuum members 54 and 56 may be formed of a single, elongated vacuum member. In other embodiments, multiple vacuum members may be used and, for example, aligned side-by-side in the feed direction. While only edge vacuum members 54 and 56 are illustrated, inboard vacuum members may also be utilized (see FIG. 14).

FIG. 4 illustrates a detail view of the vacuum member 56 and glass substrate 50. The vacuum member 56 can apply a vacuum suction force sufficient to inhibit movement (horizontal and vertical) of the edge 48 of the glass substrate 50 during a beveling process. As used herein, “vacuum suction force” refers to the cumulative area of all vacuum openings of the vacuum member 56 multiplied by the suction pressure. As can be seen, the vacuum suction force can be applied by the vacuum member 56 near to and spaced from the edge 48 of the glass substrate 50. This location of the vacuum member 56 forms an overhang region 60 of the glass substrate 50 having an overhang distance D_(OH) measured from an outer edge 62 of the vacuum member 56 where the overhang begins to the edge 48 in a direction perpendicular to the edge 48 (or feed direction). In some embodiments, the overhang distance D_(OH) may be no less than about 6 mm, such as no less than about 10 mm, such as no less than about 15 mm, such as no less than about 20 mm. In some embodiments, the overhang distance D_(OH) may be between about 5 mm and about 30 mm.

As will be described below, the vacuum member 56 is provided with an array 64 of vacuum openings 66, where one or more regions of the array 64 may have an orderly, regular or uniform distribution (e.g., rows and/or columns) of the vacuum openings 66. Such an arrangement of array 64 of vacuum openings 66 can produce a relatively flat edge 48 of the glass substrate 50 for a free hanging edge 48 during a beveling or other edge finishing process, which can improve symmetry between the first bevel-surface interface 26 and the second bevel-surface interface 28 for the horizontally oriented glass substrate 50 (FIG. 1). For example, FIG. 5 illustrates edge flatness for glass substrates having thicknesses of 0.5 mm and 0.3 mm at different overhang distances and pressure values. As can be seen, minimized vertical displacement of the glass edge can be achieved, such as less than about 0.1 mm over at least part, most or all of the length of the glass substrates.

Referring to FIG. 6, the vacuum member 56 is illustrated in isolation and includes a vacuum body 70 that provides a pressure chamber located therein and the array 64 of vacuum openings 66. The vacuum openings 66 are in communication with channels 67 (FIG. 8) that extend from a support surface 72 of the vacuum member 56 and are in communication with the pressure chamber located within the vacuum body 70. Referring briefly to FIGS. 7 and 8, in some embodiments, the support surface 72 may be provided by a compliant member 74 that is formed as a layer of compliant material (e.g., silicone, rubber, soft plastic, etc.) that is suitable for contacting the glass substrate 50 and supporting the glass substrate thereon without damage. The compliant member 74 may include the array 64 of vacuum openings 66 that register with an array 76 of openings provided by the vacuum body 70 to provide the channels 67 between the vacuum openings 66 and the pressure chamber 78 (FIG. 8). In other embodiments, the vacuum body may include slots and/or openings that do not match the array 64 of vacuum openings 66 of the support surface 72, yet can distribute negative pressure thereto from the pressure chamber 78. An outlet represented by arrow 75 may be provided to draw air or other suitable gas from the pressure chamber 78.

The vacuum member may be a single-piece or multi-piece configuration. Referring to FIG. 9, for example, a vacuum member 81 may have a vacuum body 83 having a single-piece monolithic configuration. The vacuum body 83 may include a pressure chamber 85 provided therein and a connect arrangement 87 that is formed as part of the vacuum body 83, separate from the pressure chamber 85 that allows the vacuum member 82 to be connected to a glass transport system. Inlet 77 and outlet 79 may supply positive and negative pressure to the pressure chamber 85. FIG. 10 illustrates a multi-piece configuration where a vacuum member 91 includes a vacuum body 93 formed by a chamber housing member 95 and a cap member 97. A connect arrangement 99 may be provided for connecting the vacuum member 91 to a glass transport system.

Referring again to FIG. 6, the vacuum openings 66 of the array 64 may be located in both rows R₁-R_(x) and columns C₁-C_(x), thereby providing localized suction points. In this example, the vacuum openings 66 in a particular row R have substantially the same width, or, in this example, radius (e.g., no more than about 5 mm, such as 2 mm or less) and are each spaced-apart equally from each other along the particular row R. In other embodiments, one or more of the vacuum openings may have one or more different radii. As one example, adjacent vacuum openings 66 may be spaced equally about 20 mm across the particular row R. In other embodiments, the spacing between adjacent vacuum openings 66 may be less than 20 mm, such as about 15 mm or about 10 mm or even less, depending, for example, on the size of the glass substrate, the type of finishing operation, etc. In the embodiment of FIG. 6, the vacuum openings 66 are equally spaced-apart 10 mm center-to-center as represented by S₁.

The vacuum openings 66 in a particular column C have substantially the same radius (e.g., no more than about 5 mm, such as about 2 mm or less) and are each spaced-apart equally from each other along the particular column C. In other embodiments, one or more of the vacuum openings may have one or more different radii. As one example, adjacent vacuum openings 66 may be spaced equally about 20 mm along the particular column C. In other embodiments, the spacing between adjacent vacuum openings 66 along the particular column C may be less than 20 mm, such as about 15 mm or about 10 mm or even less, depending, for example, on the size of the glass substrate, the type of finishing operation, etc. In the embodiment of FIG. 6, the vacuum openings 66 are equally spaced-apart 10 mm center-to-center as represented by S₂, forming a rectangular matrix of vacuum openings.

Any suitable array of vacuum openings forming localized suction points may be used. In some embodiments, an array having about 25 vacuum openings to about 200 vacuum openings per 100 cm² having a width (or diameter) of no more than about 10 mm, such as 4 mm or less may be provided. In the embodiment of FIG. 6, the array 64 has about 100 vacuum openings 66 per 100 cm².

FIGS. 11-13 illustrate other vacuum member embodiments having other array configurations for vacuum openings. In the embodiment of FIG. 11, a vacuum member 80 includes many of the features described above with regard to vacuum member 56. In this exemplary embodiment, the vacuum member 80 includes an array of vacuum openings 84 located in both rows R₁-R_(x) and columns C₁-C_(x), thereby providing localized suction points. In this embodiment, however, the row spacing S₁ is greater than the column spacing S₂ along the column. FIG. 12 illustrates another exemplary embodiment of a vacuum member 81 where the row spacing S₁ along the row is greater than the column spacing S₂ along the column. FIG. 13 illustrates another embodiment of a vacuum member 86 where the row spacing S₁ along the row is greater than the column spacing S₂ along the column. In this embodiment, the rows are offset from each other forming diagonal columns. The Table below illustrates certain properties of the vacuum member embodiments depicted by FIGS. 5 and 11-13 under an applied pressure of 50 KPa using a 0.2 mm thick glass substrate. These values are merely exemplary and not meant to be limiting.

TABLE Vacuum Member Embodiments Suction Vacuum Reac- Maximum Slots Suction tion Principal Embodi- Total Area Force Force Stress ment Description (mm²) (N) (N) (MPa) FIG. 5 R_(opening) = 2 mm 4551.0 364.1 360.1 13.7 Spacing = 10 mm (S1) and 10 mm (S2) Glass Dimensions = 0.2 mm × 925 mm × 225 mm FIG. 11 R_(opening) = 2 mm 3050.0 244.0 241.8 14.8 Spacing = 15 mm (S1) and 10 mm (S2) Glass Dimensions = 0.2 mm × 925 mm × 225 mm FIG. 12 R_(opening) = 2 mm 2312.1 185.0 182.1 17.3 Spacing = 20 mm (S1) and 10 mm (S2) Glass Dimensions 0.2 mm × 925 mm × 225 mm FIG. 13 R_(opening) = 2 mm 2263.0 181.0 159.0 17.3 Spacing = 20 mm (S1) and 10 mm (S2) Glass Dimensions 0.2 mm × 925 mm × 225 mm

As can be seen from the Table, the Maximum Principal Stress determined using finite element analysis (FEA) can result in stresses of less than 20 MPa during use, which can reduce the likelihood of glass damage near or at the edges of the glass substrate. Maximum Principal Stress is an indication of the total tensile stress effect on the glass substrate.

Referring to FIG. 14, an example glass support system 100 is illustrated (e.g., for use in the finishing apparatus of FIG. 3) that includes multiple vacuum members 102, 104, 106 and 108. As an example, the vacuum members can be any one or more of the vacuum members described above. As can be seen, vacuum members 102 and 108 are outermost vacuum members that are nearest edges 110 and 112 of a glass substrate 114 and vacuum members 104 and 106 are innermost vacuum members that are furthest from the edges 110 and 112. The vacuum members 102, 104, 106 and 108 may all be of the same dimensions (or of different dimensions) and can extend along substantially the entire length of the glass substrate 114. Overhang regions 116 and 118 may be provided, as described above, for a glass finishing operation.

Referring back to FIG. 3, once the glass substrate 50 is supported by the glass support system 46, the glass substrate 50 and the glass support system 46 are translated to an edge grinding system 120 of the finishing apparatus 40 by the glass transport system 44. The edge grinding system 120 may generally include abrasive wheel assemblies 122 and 124 that are located at the opposite edges 48 and 58 of the glass substrate 50. In other embodiments, only a single abrasive wheel assembly may be used, or there may be up to four abrasive wheel assemblies or one for each edge 48, 58, 126 and 128 of the glass substrate 50.

The abrasive wheel assemblies 122 and 124 may each include an abrasive wheel 127 that is used to grind and shape the edges 48 and 58 of the glass substrate 50 and a motor 129 that is used to rotate the abrasive wheel 127. In some embodiments, the abrasive wheel assemblies 122 and 124 may each further include drive mechanisms 130 that can be used to move the abrasive wheels 127 toward and away from the respective edges 48 and 58. A controller 135 may be provided that controls operation of the abrasive wheel assemblies 122 and 124, glass support system 46 and glass transport system 44. In the illustrated embodiment, the abrasive wheels 127 are formed wheels. However, other abrasive wheels may be used. Referring briefly to FIG. 15, the formed wheel 127 has a generally cylindrical shape and includes one or more recesses 132 that have a profile that is complimentary to the profile desired for the respective edge 48, 58 and that serve as the grinding surface of the formed wheel 127. In other embodiments, one or both of the abrasive wheels 127 may include a pair of cup wheels that contact the edge of the glass substrate 50 with their planar faces.

Referring again to FIG. 3, with the glass substrate 50 supported by the glass support system 46 including the vacuum members 54 and 56, the glass transport system 44 translates the support system 46 and the glass substrate 50 to the abrasive wheel assemblies 122 and 124 where the abrasive wheels 127 engage the edges 48 and 58 of the glass substrate 50. Referring now to FIG. 16, a representative plot illustrates decreased edge bevel asymmetry provided by the regular distribution of vacuum openings, for example, as exhibited by the vacuum member 56 of FIG. 6. As can be seen, the vacuum member 56 further stabilizes the edge 48, which maintains a relatively high degree of symmetry between the first bevel-surface interface 26 (represented by line 140) and the second bevel-surface interface 28 (represented by line 142). Represented by line 144, a factor of asymmetry (FOA) illustrates relatively small changes in the symmetry between the first bevel-surface interface 26 and the second bevel-surface interface 28. The FOA is equal to the bevel delta (difference in bevel width) between the first bevel-surface interface 26 and the second bevel-surface interface 28 and the thickness of the glass substrate 50. The higher the FOA, the less symmetry between the first bevel-surface interface 26 and the second bevel-surface interface 28.

Referring still to FIG. 16, it can be seen that the FOA may tend to increase at a front region 150 and a rear region 152 (i.e., at the corners) of the glass substrate 50. Referring to FIG. 17, this can be because stiffness of the edges 48 and 58 is relatively lower (e.g., up to 60 percent lower) at the leading and trailing corners 154, 156, 158 and 160 compared to the overall overhanging edges 48 and 58 (FIG. 3). Further, as illustrated by FIG. 18, the flexural rigidity (D) tends to remain relatively low for glass substrate thicknesses less than about 0.6 mm, becoming relatively flat at about 0.25 mm or less. The flexural rigidity (D) is a function of the Young's modulus (E), thickness (t) and Poisson's ratio (u) and is given by:

$D = {\frac{{Et}^{3}}{12\left( {1 - v^{2}} \right)}.}$

In addition to having lower stiffness, the incoming lead corners 154 and 156 of the glass substrate 50 (FIG. 3) may be subjected to direct jets of coolant fluid (e.g., water) and an abrupt impact with the abrasive wheels 127, which can cause greater vertical displacement of the glass substrate 50 during a beveling process. Edge quality close to the corners 154, 156, 158 and 160 may be lower than expected in some instances due to edge bevel asymmetry, which can lead to glass fracture and breakage issues, particularly during handling.

Referring back to FIG. 3, the finishing apparatus 40 may include edge guide assemblies 170 that provide local support to the glass edges 48 and 58 at the wheel/glass interface. As can be seen, the edge guide assemblies 170 may be located or positioned outside the vacuum members 54 and 54, stationary relative to the glass transport system 44 and between the vacuum members 54 and 56 and their respective abrasive wheel 127 for increased vertical support of the glass edges 48 and 58. FIG. 19 shows a schematic illustration of the abrasive wheel 127 and the edge guide assembly 170. In this embodiment, a guide length L that contacts and supports the glass substrate is less than or equal to a wheel diameter D of the abrasive wheel. A distance T between the edge guide assembly 170 in contact with the glass substrate 50 and the abrasive wheel 127 can be adjusted based, at least in part, on the glass thickness to minimize the overhang distance D_(OH), which can provide increased edge stability.

Referring to FIG. 20, a schematic illustration of the edge guide assembly 170 includes a lower edge guide member 172 and an upper edge guide member 174. The lower edge guide member 172 includes a guide surface 176 that is arranged to contact a broad surface 178 of the glass substrate 50. The upper edge guide member 174 also includes a guide surface 180 facing the guide surface 176 that is arranged to contact a broad surface 182 of the glass substrate 50. The guide surfaces 176 and 180 may be solid or may be formed of moving components, such as rollers, belts, etc., as will be described below. The guide surfaces 176 and 180 may be formed of any suitable material for contacting and guiding the glass substrate 50. The edge guide assembly may further include one or more positioning actuators 184 and 186 (e.g., pneumatic cylinders) that can move one or both of the upper edge guide member 174 and lower edge guide member 172 toward and away from one another between closed and open configurations (shown by dashed lines) for positioning the glass substrate 50 during a beveling process. In other embodiments, one or both of the upper edge guide member 174 and lower edge guide member 172 may be fixed in position relative to the other.

Referring to FIGS. 21 and 22, a finishing apparatus 200 is illustrated that includes an abrasive wheel assembly 202 that includes an abrasive wheel 204 and a support structure 206 that supports the abrasive wheel 204 in the illustrated elevated, horizontal orientation. The finishing apparatus 200 may further include an edge guide assembly 208. The edge guide assembly 208 can include a lower edge guide member 210 and an upper edge guide member 212. Both the lower edge guide member 210 and the upper edge guide member 212 include rollers 205, 215 (205 in FIGS. 21 and 215 in FIG. 22) forming dynamic support surfaces configured to contact and guide an edge of a glass substrate. In the illustrated example of FIG. 21, the edge guide assembly 208 is shown in an open configuration with the upper edge guide member 212 retracted from the lower edge guide member 210 by an actuator assembly 214. The lower edge guide member 210 may be fixed in position. In some embodiments, the edge guide assembly 208 may be at least partially supported by the support structure 206 that supports the abrasive wheel 204. In some embodiments, at least a part of the edge guide assembly 208 includes its own support structure independent of the support structure 206. The actuator assembly 214 can move the upper edge guide member 212 to an extended position nearer the lower edge guide member 210 to support the edge of the glass substrate as discussed above (FIG. 22).

Referring to FIGS. 23 and 24, another finishing apparatus 220 includes an abrasive wheel assembly 222 that includes an abrasive wheel 224 and a support structure 226 that supports the abrasive wheel 224 in the illustrated elevated, horizontal orientation. The finishing apparatus 220 further includes an edge guide assembly 228. The edge guide assembly 228 includes a lower edge guide member 230 and an upper edge guide member 232. Both the lower edge guide member 230 and the upper edge guide member 232 include rollers 235 forming dynamic support surfaces configured to contact and guide an edge 234 of a glass substrate 236. In the illustrated example of FIGS. 23 and 24, the edge guide assembly 228 is shown in a closed or closing configuration with the lower edge guide member 230 extended toward the upper edge guide member 232 by an actuator assembly 238. The upper edge guide member 232 may be fixed in position.

Referring to FIG. 25, another edge guide assembly 250 is illustrated and may include a lower guide member 252 and an upper guide member 254. In this embodiment, both of the lower and upper guide members 252 and 254 include a belt assembly 256 and 258. The belt assembly 256 of the lower guide member 252 includes a belt 260 having a guide surface 262 that is suitable for contacting and guiding a glass substrate. The belt 260 may be driven and supported by end rollers 264 and 266 about which the belt 260 travels and intermediate rollers 268 that can support a section of the belt 260 between the end rollers 264 and 266. The belt assembly 258 of the upper guide member 254 includes a belt 269 having a guide surface 270 that is suitable for contacting and guiding a glass substrate. The belt 269 is driven and supported by end rollers 272 and 274 about which the belt 260 travels, without use of intermediate rollers. While the edge guide assembly 250 illustrates lower and upper guide members 252 and 254 having different roller arrangements, they may have the same roller arrangement.

Referring to FIG. 26, another edge guide assembly 280 is illustrated and includes a lower guide member 282 and an upper guide member 284. In this embodiment, both of the lower and upper guide members 282 and 284 can be formed as solid bars 286 and 288 of a material that is suitable to contact the glass substrate. The lower guide member 282 and upper guide member 284 may be spaced from each other forming a groove 290 that extends in the feed direction and is sized to receive the entire thickness of the glass substrate. In some embodiments, the groove 290 may include a lead-in portion 292 and a lead-out portion 294. The lead-in portion 292 and lead out portion 294 may be wider than the rest of the groove 290 therebetween to guide the glass substrate into and out of the groove.

Referring to FIG. 27, another edge guide assembly 300 is illustrated and includes a lower guide member 302 and an upper guide member 304. In this embodiment, the upper guide member 304 is formed as a solid bar 306 of a material that is suitable to contact the glass substrate. The lower guide member 302 has a dynamic guide surface 308 formed by rollers 310. In other embodiments, the upper and/or lower guide member may be formed using air bearings, air/pressure bearings or ultrasonic non-contact bearings.

FIG. 28 illustrates a representative plot showing decreased edge bevel asymmetry provided through use of the edge guide assembly, for example, as exhibited by the edge guide assembly 300 of FIG. 27. As can be seen, the edge guide assembly 300 further stabilizes the edge, which maintains a relatively high degree of symmetry between the first bevel-surface interface (represented by line 312) and the second bevel-surface interface (represented by line 314). Represented by line 316, an FOA illustrates relatively small changes in the symmetry between the first bevel-surface interface and the second bevel-surface interface.

The above-described glass support systems and methods can provide one or both vacuum members having an array of regularly spaced localized suction points and edge guide assemblies that can be used to decrease glass edge asymmetry during beveling or other finishing process. The decrease in glass edge asymmetry can be accomplished by reducing out-of-plane deflections of the glass substrate and presenting a flat edge to the abrasive wheel. Improving glass edge symmetry can improve glass edge strength, which can reduce the possibility of glass fracture or breakage.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents. 

What is claimed is:
 1. A glass support system, comprising: a vacuum member configured to extend lengthwise in a glass feed direction along an edge of a glass substrate, the vacuum member comprising a vacuum body including a pressure chamber located therein and a support surface including an array of vacuum openings extending therethrough and in communication with the pressure chamber; and wherein the array of vacuum openings is arranged in multiple, side-by-side rows and substantially uniform spacing between the vacuum openings along each one of the multiple rows.
 2. The glass support system of claim 1, wherein the array of vacuum openings are arranged in multiple, side-by-side columns having substantially uniform spacing between the vacuum openings along each one of the multiple columns.
 3. The glass support system of claim 1, wherein the array of vacuum openings has at least about 25 openings per 100 cm² of support surface area.
 4. The glass support system of claim 1, wherein the vacuum openings have a width of no more than about 10 mm.
 5. The glass support system of claim 1, wherein the vacuum openings have a radius of no more than about 2 mm.
 6. The glass support system of claim 1, wherein the support surface comprises a compliant material.
 7. The glass support system of claim 1, further comprising an edge guide assembly comprising an upper edge guide member and a lower edge guide member spaced from the upper edge guide member to provide a path through which the glass substrate can travel.
 8. The glass support system of claim 7, wherein at least one of the upper edge guide member and the lower edge guide member includes rollers forming a dynamic support surface configured to contact the glass substrate.
 9. The glass support system of claim 7, wherein at least one of the upper edge guide member and the lower edge guide member comprises a bar of a material that is configured to contact the glass substrate.
 10. The glass support system of claim 7, wherein at least one of the upper edge guide member and the lower edge guide member comprises a belt assembly including a belt comprising a guide surface configured to contact the glass substrate.
 11. A glass edge finishing apparatus comprising: a glass transport system; and a glass support system that is moved by the glass transport system in a glass feed direction, the glass support system configured to support a glass substrate having a thickness of no more than about 0.7 mm, the glass substrate including a generally planar surface and an out-of-plane direction normal to the generally planar surface, the glass support system comprising: a vacuum member configured to extend lengthwise in the glass feed direction and along an edge of the glass substrate, the vacuum member comprising a vacuum body including a pressure chamber located therein and a support surface comprising an array of vacuum openings with an opening density of at least about 25 openings per 100 cm² of support surface area extending therethrough and in communication with the pressure chamber.
 12. The glass edge finishing apparatus of claim 11, wherein the array of vacuum openings are arranged in multiple, side-by-side columns with substantially uniform spacing between the vacuum openings along each one of the multiple columns.
 13. The glass edge finishing apparatus of claim 12, wherein the array of vacuum openings are arranged in multiple, side-by-side rows with substantially uniform spacing between the vacuum openings along each one of the multiple rows.
 14. The glass edge finishing apparatus of claim 11, wherein the vacuum openings have a width of no more than about 10 mm.
 15. The glass edge finishing apparatus of claim 11, wherein the vacuum openings have a width of no more than about 4 mm.
 16. The glass edge finishing apparatus of claim 11, wherein the support surface comprises a compliant material.
 17. The glass edge finishing apparatus of claim 11, further comprising an edge guide assembly comprising an upper edge guide member and a lower edge guide member spaced from the upper edge guide member to provide a path through which the glass substrate can travel.
 18. The glass edge finishing apparatus of claim 17, wherein at least one of the upper edge guide member and the lower edge guide member includes rollers forming a dynamic support surface configured to contact the glass substrate.
 19. The glass edge finishing apparatus of claim 17, wherein at least one of the upper edge guide member and the lower edge guide member comprises a bar of a material that is configured to contact the glass substrate.
 20. The glass edge finishing apparatus of claim 17, wherein at least one of the upper edge guide member and the lower edge guide member comprises a belt assembly including a belt comprising a guide surface configured to contact the glass substrate.
 21. The glass edge finishing apparatus of claim 17, further comprising an abrasive wheel assembly configured to bevel the edge of the glass substrate.
 22. A method of finishing an edge of a glass substrate, the method comprising: supporting the glass substrate on a glass support system, the glass substrate comprising a generally planar surface and thickness equal to or less than about 0.7 mm and an out-of-plane direction normal to the generally planar surface, the glass support system comprising: a vacuum member configured to extend lengthwise in the glass feed direction and along an edge of the glass substrate, the vacuum member comprising a vacuum body including a pressure chamber located therein and a support surface comprising an array of vacuum openings with an opening density of at least about 25 openings per 100 cm² extending therethrough and in communication with the pressure chamber; applying a negative pressure through the array of vacuum openings to the generally planar surface; and beveling the edge of the glass substrate using an abrasive wheel assembly.
 23. The method of claim 22, further comprising supporting the glass substrate using an edge guide assembly comprising an upper edge guide member and a lower edge guide member spaced from the upper edge guide member to provide a path through with the glass substrate can travel.
 24. The method of claim 22, wherein the array of vacuum openings are arranged in multiple, side-by-side columns with substantially uniform spacing between the vacuum openings along each one of the multiple columns.
 25. The method of claim 24, wherein the array of vacuum openings are arranged in multiple, side-by-side rows with substantially uniform spacing between the vacuum openings along each one of the multiple rows.
 26. The method of claim 22, further comprising positioning the glass substrate on the vacuum member providing an overhang between the vacuum member and the edge of the glass substrate.
 27. A glass edge finishing apparatus comprising: a glass transport system; a glass support system movable in a glass feed direction by the glass transport system, the glass support system configured to support a glass substrate having a thickness of no more than about 0.7 mm, the glass substrate having a generally planar surface and an out-of-plane direction normal to the generally planar surface, the glass support system comprising: a vacuum member configured to extend lengthwise along an edge of the glass substrate in the glass feed direction, the vacuum member comprising a vacuum body including a pressure chamber located therein and a support surface comprising a plurality of vacuum openings extending therethrough and in communication with the pressure chamber; an abrasive wheel assembly configured to bevel the edge of the glass substrate as the glass substrate is moved by the abrasive wheel assembly in the glass feed direction by the glass transport system; and an edge guide assembly located between the abrasive wheel assembly and the vacuum member comprising an upper edge guide member and a lower edge guide member spaced from the upper edge guide member to provide a path through which the glass substrate can travel.
 28. The glass edge finishing apparatus of claim 27, wherein at least one of the upper edge guide member and the lower edge guide member includes rollers forming a dynamic support surface configured to contact the glass substrate.
 29. The glass edge finishing apparatus of claim 27, wherein at least one of the upper edge guide member and the lower edge guide member comprises a bar of a material that is configured to contact the glass substrate.
 30. The glass edge finishing apparatus of claim 27, wherein at least one of the upper edge guide member and the lower edge guide member comprises a belt assembly including a belt having a guide surface configured to contact the glass substrate. 